#include <stdio.h>
extern long dvar();
int expector(long input) {
	long expected = 13*input;
	long result = dvar(input);
	if (result!=expected) {
		fprintf(stderr,"Error: For input %ld we expected %ld but got %ld\n",input, expected, result);
		return 0;
	} else {
		fprintf(stderr,"OK: For input %ld we expected %ld and got %ld\n",input, expected, result);
	}
	return 1;
}
RET( expector(0) && expector(1) && expector(123) && expector(-1) && expector(-333) );
